Add length check to prevent index out of range (#4864)

2017-10-23 00:21:34 -05:00
parent ed7f68ca9b
commit eba15dc3f5
1 changed files with 1 additions and 1 deletions
--- a/plan/stats.go
+++ b/plan/stats.go
@ -74,7 +74,7 @@ func (p *DataSource) getStatsProfileByFilter(conds expression.CNFExprs) *statsPr
 	}
 	for i, col := range p.Columns {
 		hist, ok := p.statisticTable.Columns[col.ID]
-		if ok && hist.NDV > 0 {
+		if ok && hist.NDV > 0 && len(hist.Buckets) > 0 {
 			factor := float64(p.statisticTable.Count) / float64(hist.Buckets[len(hist.Buckets)-1].Count)
 			profile.cardinality[i] = float64(hist.NDV) * factor
 		} else {